Coherer Receiver

Meiser & Mertig; Dresden

Data
Forum
Pictures
Collections

  • Year
  • 1900 ?
  • Category
  • Morse-Equipment & TTY, RTTY, TDD etc.
  • Radiomuseum.org ID
  • 258191

 Technical Specifications

  • Wave bands
  • Long Wave and/or Very Low Frequency (VLF).
  • Power type and voltage
  • Dry Batteries
  • Loudspeaker
  • - For headphones or amp.
  • Material
  • Various materials
  • from Radiomuseum.org
  • Model: Coherer Receiver - Meiser & Mertig; Dresden
  • Shape
  • Tablemodel, with any shape - general.
  • Notes

  • Circa 1900 Meiser & Mertig Coherer Receiver. This receiver was built shortly after Marconi built his: Black Box" Coherer Receiver and was almost identical to it electrically. 

  • Author
  • Model page created by Alan Larsen. See "Data change" for further contributors.

 Collections | Museums | Literature

 Forum

Forum contributions about this model: Meiser & Mertig;: Coherer Receiver

Threads: 2 | Posts: 5

I am looking for information about this manufacturer. There is a coherer receiver in the Spark Museum from Meisner and Mertig (approx. 1900), but the museum does not have any info about this manufacturer

Kind regards

Nico

 

Attachments

Nicolaas van Dijk, 24.Feb.15

Weitere Posts (3) zu diesem Thema.

A while ago I started to build a polair relais for a coherer receiver with the idea to do testing and perhaps building a complete receiver. With the help and a whole lot of information from Nikolaus Lowe (to whome I am very gratefull), I did build a relais that did switch at a voltage of approx 1 Volt and with an impedance of 2.5 kOhm (when adjusted well) 

At internet I found pictures of the receiver friom Meisner and Mertig in a museum. I did contact the museum and inmedeately received pictures from which I started to build such a receiver using the relais.

The coherer has copper electrodes and RVS metal filings. Iron metal filigs worked perfectly, but were easily magnetisised wich impaired the correct functioning of the coherer. 

The only thing still to be made is the wooden base, but I tested the receiver and did like to share the results. 

The sensitivity is good, when you approximate the gain of such a receiver, it is amazing. 
 
 I measured the input impedance with an open coherer and a CW signal of - 30 dBm. It was in the order of 1 kOhm at 1-10 MHz. The peak RF voltage measured at the input generated by the spark of a BBQ lighter was approx 100 mV. at the threshold where the coherer detects.
That means that the detected input power was approx 10 uW.
I could easily swith a 1 Watt load at the output resulting in an approximated gain of 50 dB!!!!
In order to get a reliable decoheracion (is that correct English or did I invent a new word?), the coherer has to be attached a little sloppy. When attached firmly, the decoherer sometimes does not function and ticks twice.
It is really fun to experiment with coherers, highly recomended!!. 
Kind regards
Nico
 

Attachments

Nicolaas van Dijk, 22.Feb.15

Weitere Posts (2) zu diesem Thema.